Ultrathin Strike Plating for Copper Lead Frame Oxidation
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Solution Overview
Problem
Conventional lead frame manufacturing for semiconductor devices faces challenges in preventing oxidation of the base layer, leading to increased manufacturing costs and failure rates, while also complicating the process.
Innovation Solution
The use of strike plating and self-assembly monolayer materials to form a copper-based lead frame, with strike plating layers of gold, silver, or palladium, and a self-assembly monolayer, which prevents oxidation and simplifies the manufacturing process by reducing the thickness of the plating layers to 20-100 nm, thereby enhancing bonding and reducing failure rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plating methods are used to prevent oxidation of the base layer, then oxidation prevention is achieved, but manufacturing cost increases and process complexity increases
Solution Approach 1:
The patent changes the thickness parameter of the plating layer from conventional thick plating to ultrathin plating of 20-100 nm. This parameter change maintains oxidation prevention functionality while dramatically reducing material consumption and manufacturing cost. The ultrathin plating achieves sufficient protective effect at minimal thickness, resolving the contradiction between reliability and manufacturing cost.
Solution Approach 2:
The patent applies ultrathin plating selectively to specific surfaces of the lead frame base layer that require oxidation protection, rather than uniformly thick plating throughout. This local quality approach concentrates protective functionality where needed while minimizing overall material usage and cost, addressing the contradiction between effective oxidation prevention and manufacturing cost.
2Reliability
If conventional plating methods are used to prevent oxidation of the base layer, then oxidation prevention is achieved, but manufacturing process becomes complicated
Solution Approach 1:
By changing the plating thickness parameter to ultrathin 20-100 nm range, the patent simplifies the manufacturing process. The ultrathin plating requires fewer processing steps, shorter plating time, and easier process control compared to conventional thick plating, thereby reducing manufacturing process complexity while maintaining oxidation prevention effectiveness.
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate processing steps from the conventional plating process. The ultrathin plating method allows direct plating without requiring multiple intermediate treatments, simplifying the overall manufacturing process while achieving the same oxidation protection function, thus reducing process complexity.
3Ease of manufacture
If plating layer thickness is reduced to 20-100 nm, then manufacturing cost is reduced and process is simplified, but bonding strength may be compromised
Solution Approach 1:
The patent uses composite material structure with ultrathin plating layers of specific materials (such as palladium, silver, or copper) on the base layer. These materials are selected for their excellent bonding properties and oxidation resistance. The composite structure of base layer plus ultrathin functional plating maintains bonding strength while reducing overall material cost and simplifying the process.
Solution Approach 2:
The patent optimizes the plating thickness parameter to 20-100 nm, which is sufficient to provide bonding functionality and oxidation protection without excessive material. This parameter optimization ensures adequate bonding strength for wire bonding operations while minimizing material cost, resolving the contradiction between manufacturing cost and bonding strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents oxidation of the base layer, simplifies the manufacturing process, reduces costs, and enhances the bondability of conductive wires to the lead frame, thereby improving the reliability and efficiency of the semiconductor device assembly.
Implementation Method 1
a first strike plating layer formed on one or more portions, or the entire surface of the base layer, wherein the first strike plating layer is formed by plating at least one selected from gold, silver and palladium using a strike plating method
Implementation Method 2
a self assembly monolayer coated on one or more portions, or the entire surface of the first strike plating layer
Data Source
AI summary
Provided is a lead frame for a semiconductor device, which includes a base layer made of copper, a strike plating layer or a self assembly monolayer (SAM), thereby preventing oxidation of a base layer while simplifying the manufacturing process, reducing the manufacturing costs and reducing a failure ratio. In one embodiment, in the lead frame for a semiconductor device including a die pad and a plurality of leads positioned adjacent to each other around the die pad, the lead frame includes a base layer made of copper; and a first strike plating layer formed on the one or more portions of the surface of the base layer.